An analysis of 15 years of data from the European Organization for Research and Treatment of Cancer study 10853 shows women with ductal carcinoma in situ (DCIS), the earliest stage of breast cancer, may reduce their risk of the cancer coming back by as much as 50 percent when treated with radiation therapy after lumpectomy.

The study compared rates of cancer returning in women with DCIS who were treated with lumpectomy alone with those of women who had lumpectomy followed by radiation therapy.

Background

In DCIS, often called pre-invasive or stage 0 breast cancer, cancer cells are only in the ducts of the breast, the passages through which milk flows to the nipple. Because the cancer is contained, most women with DCIS are treated with either surgery alone, or surgery followed by radiation therapy.

Whether radiation therapy is necessary for all women with DCIS has been debated in the medical community. Researchers of the EORTC 10853 study, begun in 1986, explored the long-term impact of radiation therapy by observing the time from joining the trial to local recurrence, or the appearance of DCIS, and invasive local recurrence, or breast cancer that came back as stage I to III in the same breast as the original cancer.

Researchers also assessed rates of:

regional recurrence, cancer that returns to the lymph nodes of the collar bone or armpit

contralateral breast cancer, cancer that occurs in the other breast

distant metastasis, cancer that spreads beyond the breast and nearby lymph nodes to other organs of the body

breast cancer-specific survival, the time from enrolling in the trial to breast cancer-related death, and

overall survival, the time from starting the study to death from any cause

Design

A total of 1,010 women with DCIS who were treated with lumpectomy were assigned to one of two groups:

Lumpectomy followed by standard radiation therapy (507 women)

Lumpectomy with no further treatment (503 women)

Results

After 15 years of data collection, the trial team found that

about 23 percent of all participants had a local recurrence (48 percent of the returning cancers were DCIS and 52 percentwereinvasive)

nearly half as many women in the group receiving radiation therapy had a local recurrence as in the group receiving lumpectomy alone (149 with lumpectomy alone, 85 with lumpectomy plus radiation)

the risk of local recurrence was greatest in the first 5 years after treatment, and decreased from years 5 – 10, and again from years 10 – 15. Most recurrences occurred within 10 years of treatment

radiation therapy was effective in helping reduce rates of recurrence regardless of age, the tumor type and hormone status, and whether there was evidence of cancer after surgery

The researchers also found that there were no significant differences in survival categories among the groups after a recurrence occurred. Overall survival couldn’t be measured because of the small number of participants in the study. Yet, radiation therapy reduced the risk of invasive recurrences, which ultimately led to better outcomes for the patient

What This Means for You

If you have DCIS, you will likely be offered treatment with either lumpectomy followed by radiation therapy, today’s standard of care, or mastectomy, the removal of the whole breast, without radiation therapy. Your surgeon and radiation oncologist may recommend one or the other depending on the extent of the area affected by DCIS, your general health, and the tumor grade, or how quickly the cancer is likely to grow and what it looks like under a microscope. Depending on your individual situation, you may be offered hormonal therapy, which was not evaluated in this study.

The findings of this study show that having radiation therapy after removing the cancer may help prevent the cancer from returning, either as DCIS or as an early-stage invasive breast cancer. Though rates of survival after a recurrence of DCIS, defined in this study as a local recurrence, were about the same whether a woman was treated with radiation or not, investigators believe this is because DCIS generally has high survival rates, given that it is pre-invasive.

Talk with your radiation oncologist about the pros and cons of following lumpectomy with radiation therapy. He or she will be able to advise you about which is best for you.